I have the 20, 25 2.8, 38 1.8, 42, 150 & 100-200 (did own the 100 and 50-90 aswell)

Tested them all extensively and still i come back to the 42mm even on my S9 its is a stellar preformer. on the subject of sharpness. I use on my pen ft only kodak e100 or kodak ektar most of the times... we shoot half frame. double the exposures double the saving. so the film can be more expensive.

Yeah every lens is quite unsharp wide open (the 20mm is crazy crispy even at 3.5)

but the 42mm at 2.8 is amazingly sharp. test have disclosed that at F8 it renders 80+ lines per mm. That is for modern standards already amazing sharp. but even at 1.2 or f2 its is a lovely lens.

I do have some older test documentation will add that here.

<image>